Several buoy configurations are described in U.S. Pat. No. 5,305,703, the disclosure of which is incorporated by reference in its entirety. One of the described embodiments is a buoy having an upper surface which essentially a flat disk. This buoy is secured to the bottom of the vessel by means of a differential hydrostatic pressure created by a pump aboard the vessel. However, the mooring of a buoy having a flat top presents a problem in that the buoy may not be centered with respect to the mooring recess when it is forced onto the hull of the vessel by the differential hydrostatic pressure. This problem has been addressed by simply stopping the pump, releasing the mooring buoy and trying again. In rough seas, this procedure may lead to numerous mooring attempts before a satisfactory position of the mooring buoy is achieved. This is a time consuming and risky procedure.